An ideal LCD backlight system should have high efficiency and uniform intensity profile. A typical application of colored LED in backlighting of LCD is shown in FIG. 1. The LCD backlight system 100 includes a plurality of LEDs 110, polarizers 120 and LCD panels 130. The LEDs 110, labeled as R, G, and B, representing the 3 primary colors of red, green, and blue, respectively, are placed at a certain spacing S apart. The LCD system 100 is also placed at a thickness T away from the LEDs 110. In this case, the efficiency is limited by the polarizer, in which, more than half of the absorbed light is of the wrong polarization. The uniformity is dependent on the spacing of the LEDs and the thickness. The thicker the LCD system 100 and the narrower the spacing S, the emission from the various colored LEDs 110 will overlap more. Thereby requiring a high density LED population and thick display to achieve a uniform display with the typical LCD backlight system 100. High density of LED population and thick display are both undesirable in practical application of LCD display backlight system.
Accordingly, the present invention proceeds upon desirability of providing LCD display backlighting system with high efficiency and uniform intensity profile using less LEDs than typical LCD display backlight system by recycling polarized light, reducing the thickness of the display and increasing the spacing of the LEDs.